Late Primary Infection Research Articles

Antimicrobials use and infection hospital contacts as proxies of infection exposure at ages 0–2 years and risk of infectious mononucleosis

Infectious mononucleosis (IM) often results from late primary infection with Epstein–Barr virus (EBV). Exposure to EBV at ages 0–2 years from, e.g., siblings therefore protects against IM. Using Danish registers, we therefore followed children born in 1997 through 2015 from age 3 years for a hospital contact with an IM diagnosis as outcome with the number of antimicrobial prescriptions filled before age 3 years as a proxy of infection pressure and the main exposure in stratified Cox regressions. The main analyses used sibships as strata primarily to adjust for health-seeking behaviour with further possible adjustments for age, sex, calendar period and sibship constellation. In these analyses we followed 7087 children, exposed on average to 3.76 antimicrobials prescriptions. We observed a crude hazard ratio for IM per unit increase in cumulative antimicrobial use of 1.00 (95% confidence interval 0.99, 1.02), with similar results in adjusted analyses. The hypothesis that children with the largest use of antimicrobials at ages 0–2 years would subsequently have the lowest risk of IM within a sibship was not corroborated by the data. Furthermore, sibship-matched analyses provided no support for some common early-life immune system characteristics being predictive of IM.

Seroprevalence of Epstein-Barr virus infection in children during the COVID-19 pandemic in Zhejiang, China.

We aimed to investigate the seroprevalence of Epstein-Barr virus (EBV) infection in children before and during the COVID-19 pandemic. All children admitted to the Children's Hospital Affiliated to Zhejiang University from January 2019 to December 2021 with suspected EBV-associated disease and EBV antibodies were detected by a two-step indirect method of chemiluminescence technology. A total of 44,943 children were enrolled in this study. The seroprevalence of EBV infections was compared from January 2019 to December 2021. The total seropositive rate of EBV infections was 61.02% between January 2019 and December 2021, and the seropositive trend decreased year by year. The total number of seropositive EBV infections in 2020 was reduced by 30% compared to that in 2019. In particular, nearly 30% and 50% reductions in the number of acute EBV infections and EBV reactivations or late primary infections from 2019 to 2020 were found, respectively. The number of acute EBV infections in children aged 1-3 years and EBV reactivation or late primary infection in children aged 6-9 years in 2020 sharply dropped by approximately 40% and 64% compared to that in 2019. Our study further demonstrated that the prevention and control measures for COVID-19 in China had a certain effect on containing acute EBV infections and EBV reactivations or late primary infections.

First Report on the Occurrence of a New Pathotype, 714, of Plasmopara halstedii (Sunflower Downy Mildew) in Hungary

Downy mildew of sunflower, caused by Plasmopara halstedii (Farlow) Berlese et de Toni, is an economically important disease in Hungary and much of Europe. The known pathotypes (races) of the pathogen influence the resistance genes (Pl genes) incorporated into new sunflower hybrids to manage the disease. There are at least 36 pathotypes of P. halstedii worldwide (3), but the number of races is increasing rapidly. In 2010, race 704 was identified in Hungary for the first time (2). Race 704 has been reported to confer virulence on Pl6, a broad spectrum resistance gene that is widely used in sunflower hybrids. This has coincided with a significant increase in disease severity since 2010 in the country. Our objectives are to continuously monitor this pathogen and identify pathotypes of P. halstedii. Because of the unfavorable weather conditions for downy mildew in 2013, samples were collected at a single site (Kunszentmárton, South Hungary) in the beginning of July from NK Neoma sunflower hybrids. Disease incidence (early and late primary infection) was as high as 40%. Systemically mildewed plants showed severe stunting and leaf chlorosis, signs and symptoms consistent with downy mildew. P. halstedii was identified microscopically. Examination of isolates was carried out using a set of sunflower differential lines based on the internationally standardized method for race identification of P. halstedii (1). Inoculum of the isolates was increased on a susceptible cultivar (cv. Iregi szürke csíkos) and tested by inoculating 3-day-old seedlings of sunflower differential lines. Inoculated seedlings were planted in trays in glasshouse. After 8 to 9 days, seedlings were sprayed with distilled water, covered with black plastic bags, and left overnight to induce sporulation. Disease incidence was determined by examining cotyledons at 9 days after inoculation for sporulation and true leaves on 12 to 13 days after inoculation for secondary symptoms, such as leaf chlorosis and stunting (1). While several differential lines showed no typical susceptible/resistant reactions, i.e., the infection was much lower than 100%, it was concluded that the isolates were mixtures of different P. halstedii pathotypes. To obtain single isolates, we collected zoosporangia from the differential lines in question separately, and then inoculated the seedlings of the same genotype and a uniformly susceptible line. A single isolate caused as high as 100% infection on HA-335, containing resistance gene Pl6. Subsequent evaluation of this isolate with the entire differential set resulted in an aggregate virulence phenotype of 714. As resistance gene Pl6 is incorporated to the majority of sunflower hybrids grown in Hungary, pathotypes virulent on this gene, such as 704 and 714, are likely to spread. This underscores the need to prove the resistance to these races in the newly registered hybrids and for further research to identify P. halstedii pathotypes. It is also important to establish the identity of this new pathotype by already discovered 714 pathotypes in other countries like France and Italy and to discover the real conditions of local evolving of new pathogens. To our knowledge, this is the first report of pathotype 714 of P. halstedii in both Hungary and Central Europe.

Activation of MSRV-Type Endogenous Retroviruses during Infectious Mononucleosis and Epstein-Barr Virus Latency: The Missing Link with Multiple Sclerosis?

The etiology of multiple sclerosis (MS) is still unclear. The immuno-pathogenic phenomena leading to neurodegeneration are thought to be triggered by environmental (viral?) factors operating on predisposing genetic backgrounds. Among the proposed co-factors are the Epstein Barr virus (EBV), and the potentially neuropathogenic HERV-W/MSRV/Syncytin-1 endogenous retroviruses. The ascertained links between EBV and MS are history of late primary infection, possibly leading to infectious mononucleosis (IM), and high titers of pre-onset IgG against EBV nuclear antigens (anti-EBNA IgG). During MS, there is no evidence of MS-specific EBV expression, while a continuous expression of HERV-Ws occurs, paralleling disease behaviour. We found repeatedly extracellular HERV-W/MSRV and MSRV-specific mRNA sequences in MS patients (in blood, spinal fluid, and brain samples), and MRSV presence/load strikingly paralleled MS stages and active/remission phases. Aim of the study was to verify whether HERV-W might be activated in vivo, in hospitalized young adults with IM symptoms, that were analyzed with respect to expression of HERV-W/MSRV transcripts and proteins. Healthy controls were either EBV-negative or latently EBV-infected with/without high titers of anti-EBNA-1 IgG. The results show that activation of HERV-W/MSRV occurs in blood mononuclear cells of IM patients (2Log10 increase of MSRV-type env mRNA accumulation with respect to EBV-negative controls). When healthy controls are stratified for previous EBV infection (high and low, or no anti-EBNA-1 IgG titers), a direct correlation occurs with MSRV mRNA accumulation. Flow cytometry data show increased percentages of cells exposing surface HERV-Wenv protein, that occur differently in specific cell subsets, and in acute disease and past infection. Thus, the data indicate that the two main links between EBV and MS (IM and high anti-EBNA-1-IgG titers) are paralleled by activation of the potentially neuropathogenic HERV-W/MSRV. These novel findings suggest HERV-W/MSRV activation as the missing link between EBV and MS, and may open new avenues of intervention.

Maternal and perinatal factors associated with hospitalised infectious mononucleosis in children, adolescents and young adults: record linkage study.

BackgroundThere is current interest in the role of perinatal factors in the aetiology of diseases that occur later in life. Infectious mononucleosis (IM) can follow late primary infection with Epstein-Barr virus (EBV), and has been shown to increase the risk of multiple sclerosis and Hodgkin's disease. Little is known about maternal or perinatal factors associated with IM or its sequelae.MethodsWe investigated perinatal risk factors for hospitalised IM using a prospective record-linkage study in a population in the south of England. The dataset used, the Oxford record linkage study (ORLS), includes abstracts of birth registrations, maternities and in-patient hospital records, including day case care, for all subjects in a defined geographical area. From these sources, we identified cases of hospitalised IM up to the age of 30 years in people for whom the ORLS had a maternity record; and we compared perinatal factors in their pregnancy with those in the pregnancy of children who had no hospital record of IM.ResultsOur data showed a significant association between hospitalised IM and lower social class (p = 0.02), a higher risk of hospitalised IM in children of married rather than single mothers (p < 0.001), and, of marginal statistical significance, an association with singleton birth (p = 0.06). The ratio of observed to expected cases of hospitalised IM in each season was 0.95 in winter, 1.02 in spring, 1.02 in summer and 1.00 in autumn. The chi-square test for seasonality, with a value of 0.8, was not significant.Other factors studied, including low birth weight, short gestational age, maternal smoking, late age at motherhood, did not increase the risk of subsequent hospitalised IM.ConclusionsBecause of the increasing tendency of women to postpone childbearing, it is useful to know that older age at motherhood is not associated with an increased risk of hospitalised IM in their children. We have no explanation for the finding that children of married women had a higher risk of IM than those of single mothers. Though highly significant, it may nonetheless be a chance finding. We found no evidence that such perinatal factors as birth weight and gestational age, or season of birth, were associated with the risk of hospitalised IM.

A mechanistic model simulating primary infections of downy mildew in grapevine

A dynamic model for Plasmopara viticola primary infections on grapevine was elaborated according to a mechanistic approach. Development of the sexual stage of the pathogen was split into different state variables, in which changes from one state to another were regulated by rates depending on environmental conditions. The conceptual model was based on the definition of a primary inoculum season, a seasonal oospore (inoculum) dose, and its division into many coeval cohorts. Each cohort progresses along the primary infection cycle (production and survival of sporangia, release, survival and dispersal of zoospores, infection, appearance of disease symptoms) simultaneously, with a time step of one hour. The model was evaluated over a 12-year period (1995–2006) in Emilia-Romagna (Northern Italy) by comparing simulations with actual observations of the first seasonal symptoms of downy mildew in 43 vineyards. This data set was not used in model building and represents different environmental conditions, with both early and late primary infections. The model showed high sensitivity, specificity and accuracy. The achieved probabilities that an oospore cohort produce or not an infection were 0.994 and 0.999, respectively, while there was practically no probability that an oospore cohort produce infection when infection is not predicted by the model. Because of a small probability (<0.01) that a predicted infection is not a true infection, confidence in prediction of non-infections was higher than in prediction of infections. Most of the wrong positive predictions occurred in early season, when the host was in the earlier growth stages, or when the oospore germination was triggered by isolated weak rain events. Considering that neither calibration nor empirical adjustment of model parameters were necessary to obtain accurate simulation, it was concluded that this model produces a reasonable approximation of the primary infection processes underlying oospore development. The model showed that 86% of the oospore cohorts failed infection, because sporangia did not survive till zoospore release (5.6% of these cohorts), zoospores released from sporangia did not survive until dispersal (83.6%), or the zoospores that dispersed to leaves did not cause infection (10.8%).

Prevalence of primary versus reactivated Epstein-Barr virus infection in patients with VCA IgG-, VCA IgM- and EBNA-1-antibodies and suspected infectious mononucleosis

Background In Epstein-Barr virus (EBV) infection, IgG- and IgM-antibodies to viral capsid antigen (VCA) and IgG-antibodies to Epstein-Barr nuclear antigen 1 (EBNA-1) can occur simultaneously both in late primary infection and during subclinical viral reactivation in immunocompetent persons, and the differential diagnosis is of importance. Objectives To study the prevalence of primary infection and serological reactivation in patients with suspected primary EBV infection and with all three parameters present. Study design Fifty serum samples from 43 consecutive patients referred for suspected infectious mononucleosis and positive for VCA IgG-, VCA IgM- and EBNA-1-antibodies by EIA, were tested for IgG-antibody avidity with an EBV IgG immunoblot. Sera were also tested for heterophile antibodies (HA). To verify the presence of IgM-antibodies an EBV IgM immunoblot was performed when high-avidity IgG-antibodies were found. Results and conclusions Of 43 patients with suspected primary EBV infection and VCA IgG-, VCA IgM- and EBNA-1-antibodies present, only 18 patients (42%) had a late primary infection. Twenty-one patients (49%) had high-avidity IgG-antibodies, indicating an IgM response due to reactivation, thus suggesting other causes for their symptoms. In 10 of these 21 patients the presence of IgM-antibodies was confirmed by immunoblot, indicating reactivation as a cause of IgM-antibodies in at least 23% of the 43 patients studied. Of 18 patients with primary infection, HA were detected in 16 (94%) of 17 patients tested. Only one (5%) of the patients with high-avidity antibodies had HA. Absence of HA in patients with this serological pattern is therefore a good indicator of reactivation, and conversely, the presence of HA is a good indicator of primary infection. In HA negative patients, avidity testing could be used for differential diagnosis.

Differential diagnosis of primary and reactivated Epstein-Barr virus infection

Background: In Epstein-Barr virus (EBV) infection, VCA IgG-, VCA IgMand EBNA-1antibodies can occur simultaneously both in late primary infection and during subclinical viral reactivation. The presence of all three parameters is commonly interpreted as representing a late primary infection, but supplemental testing is needed to differentiate between these stages of infection. Aim: To study the occurrence of primary infection and reactivation in patients suspected of primary EBV infection and with all three parameters present. Methods: Fifty serum samples from 43 consecutive patients referred for suspected infectious mononucleosis and positive for VCA IgG-, VCA IgMand EBNA-l-antibodies by Novitec EIA (Hiss Diagnostics, Freiburg, Germany), were tested for IgG-antibody avidity with recomLine EBV immunoblot (Mikrogen, Martinsried, Germany). Sera were also tested for heterophile antibodies (HA) with Clearview rapid test (Unipath limited, Bedford, UK). Results and Discussion: Immunoblot with avidity testing gave conclusive results in 39 (91%) patients, of which 18 (46%) had a primary infection, and 21 patients (54%) had high-avidity IgGantibodies, indicating an IgM response due to reactivation. Of the 18 patients with primary infection, HA was detected in 16 (94%) of the 17 patients tested. Only one (5%) of the patients with high-avidity antibodies had HA. Conclusion: In 39 patients with suspected primary EBV infection and both VCA IgG-, VCA IgMand EBNA-l-antibodies present, less than half (46%) had a late primary infection, whereas 52% had a probable reactivation with reappearance of VCA IgM-antibodies or past infection. The presence of HA is a good indicator of primary infection. In HA-negative patients, avidity testing should be used for differential diagnosis.

Personal and family history of autoimmune diabetes mellitus and susceptibility to young-adult-onset Hodgkin lymphoma

Young-adult-onset (15-44 years of age) Hodgkin lymphoma (HL) is believed to arise as a consequence of late primary infection in susceptible individuals. The properties of this susceptibility remain little understood. We have previously reported an increased occurrence of HL in patients with rheumatoid arthritis and among their offspring, suggesting that susceptibility to autoimmunity might be of importance also in the pathogenesis of HL. To explore this hypothesis, we assessed the association of personal and family history of diabetes mellitus, with risk of subsequent HL in a population-based case-control study, including as cases all individuals diagnosed with HL above 15 years of age 1964-1999 (n = 6,873) in Sweden, and matched population controls (n = 12,565). First-degree relatives of cases and controls were identified through linkage with the Multi-generation Register. We identified discharges listing diabetes mellitus through linkage with the Inpatient Register (1964-2000). We used odds ratios (OR) as measures of relative risk. Cases with young-adult-onset HL were less likely to have a personal (OR =0.5, 95% CI 0.2-1.1) or family (OR =0.7, 95% CI 0.6-0.8) history of diabetes mellitus. In contrast, HL diagnosed at older ages was neither associated with a personal (OR =1.0) nor family (OR =1.0) history of diabetes mellitus. These findings suggests that characteristics of the immune system associated with conditions such as diabetes mellitus type I are of importance in the pathogenesis of young-adult-onset HL.

Human herpesvirus-6 immunoglobulin G antibodies in patients with multiple sclerosis.

To further investigate a possible correlation between human herpesvirus-6 (HHV-6) infection and multiple sclerosis by analyzing the level of HHV-6 antibodies in MS patients and healthy controls. A total of 189 serum samples from patients with multiple sclerosis (MS) in different disease stages and 190 serum samples from healthy controls matched for age and sex were analyzed for HHV-6 antibodies using a competitive ELISA. There was no difference between HHV-6 IgG titers in MS patients and controls. Two of the controls were seronegative for HHV-6 versus to none of the MS-patients. There was no apparent difference in HHV-6 titers from patients in different disease stages. This study cannot support the theory that HHV-6 is a contributing factor to the development of MS, although a seroprevalence study like this would not disclose whether a late primary infection (in puberty) with HHV-6 might affect the development of MS.

The Role of Perforation of Hilar Lymph Nodes Into the Bronchial Tree of Adults

In recent years it has been apparent that there is a decreasing incidence in the frequency of the classical caseous, ulcerative type of bronchial tuberculosis. However, localized processes appearing in the bronchial wall are observed much more often, probably as the result of involvement of the hilar lymph nodes. Increasing significance has been attached to these phenomena, particularly in adults, where attention has been drawn to the possible relation of perforation of a node into the bronchial tree and the pulmonary extension of the tuberculous disease. This aspect of primary tuberculosis in children is generally recognized. It has a well defined symptomatology in which a lymph node perforation into the bronchial tree is recognized as the most serious form, often indicating the beginning of tertiary pulmonary tuberculosis. This opinion has been strengthened within the last few years by a vast number of bronchoscopic examinations especially by the French school (Mounier-Kuhn, Le Jeune, Dufourt, Lemoine, etc.). Although reports on identical developments in adults have recently increased in number, with many cases of perforation of the bronchial walls being particularly stressed (Gyselen et al., Levi-Valenti, Boucher), clinicians and pathologists have generally refused to acknowledge such post-primary forms in adults, maintaining that there are different anatomic conditions in the bronchi and a relatively rare appearance of primary tuberculosis in adults. However, late primary Infection today is a common fact as Schwartz and Uehlinger indicated in various papers based on pathological-anatomical examinations which demonstrated that bronchogenic dissemination by perforating hilar lymph nodes is quite common. Furthermore, In thoracic surgery in cases of tuberculosis one almost always finds a large, partly caseous mass of lymph nodes closely linked to the bronchus from which it can be detached only with great difficulty. We would like to give a detailed account of our experiences in this important matter.